US4970355A - Safety device in an electrically powered machine, especially a hand-held power tool - Google Patents

Safety device in an electrically powered machine, especially a hand-held power tool Download PDF

Info

Publication number
US4970355A
US4970355A US07/377,702 US37770289A US4970355A US 4970355 A US4970355 A US 4970355A US 37770289 A US37770289 A US 37770289A US 4970355 A US4970355 A US 4970355A
Authority
US
United States
Prior art keywords
switch
socket
plug
lever
housing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US07/377,702
Other languages
English (en)
Inventor
Friedrich Haeusslein
Manfred Staebler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Assigned to ROBERT BOSCH GMBH, ROBERT-BOSCH-PLATZ 1, D-7000, STUTTGART 10, FED. REP. OF GERMANY reassignment ROBERT BOSCH GMBH, ROBERT-BOSCH-PLATZ 1, D-7000, STUTTGART 10, FED. REP. OF GERMANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: STAEBLER, MANFRED, HAEUSSLEIN, FRIEDRICH
Application granted granted Critical
Publication of US4970355A publication Critical patent/US4970355A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/66—Structural association with built-in electrical component
    • H01R13/70—Structural association with built-in electrical component with built-in switch
    • H01R13/707—Structural association with built-in electrical component with built-in switch interlocked with contact members or counterpart

Definitions

  • Our invention relates to a safety mechanism for an electrically powered machine, especially a hand-held power tool such as a drill or angle sander. It also relates to a stationary electrically powered machine such as a household appliance, which has a plug mechanism (e.g. according to DIN VDE 0625 Opera 1/11 87, 39 11, 12 und 59 or DIN German Society of Engineers 0625, Part 1, November 1987, pp. 11, 12 and 59) with a separate socket attached to a cord or power cable disconnectable from the appliance or machine and a plug built into the appliance.
  • Cords or cables are currently predominantly connected nonreleasably (i.e. the cord cannot be disconnected from the tool) with a power tool, although a hand-held power tool with the above-mentioned plug mechanism has a separable detachable power cord.
  • This current structure has several disadvantages.
  • the fixed attachment of the cord produces a bendable, slack part protruding from the outer surface of the appliance or hand-held power tool, which makes automatic manufacture particularly difficult.
  • different incompatible power grids are customary. This forces the manufacturer to market different machines according to the differences in the power grids in the different countries or to supply the machines without plugs and to place the responsibility of providing them on the customer.
  • nondisconnectable cables or power cords are prone to wear particularly in rough operating conditions; a worn-through or scraped cord attached nondisconnectably to the hand-held power tool can only be replaced by comparatively time-consuming methods.
  • an electrically powered machine especially a hand-held power tool, comprising a housing, a disconnectable cord to supply electrical energy having an attached socket, a switch position in the housing changable between an "on” and “off” position, a switch handle mounted on the housing connected mechanically with the switch for operating the switch to change the switch between the "on” and “off” position to control delivery of the electrical energy and a socket mechanism, the socket mechanism comprising the socket attached to the cord and a plug attached rigidly with the housing, the plug being connected electrically with the switch.
  • the machine further comprises a stop pawl connected mechanically with the switch handle so as to be positionable outside the housing in the vicinity of the plug to block connection of the socket with the plug, when the socket is not connected with said plug and when and as long as the switch is in the "on" position.
  • the safety device according to our invention When the safety device according to our invention is part of a hand-held power tool with a separate power cord and socket the desirable assembly and distribution features of this kind of power tool can be realized while maintaining a satisfactory level of operator safety. With the structure according to our invention, the operator cannot connect the socket to the plug if the switch is in the "on" position.
  • Separable power cords of different lengths offer a comparatively greater flexibility for the user.
  • a damaged cable or cord can be replaced in seconds rapidly by the user. Bringing the entire machine to the repair shop for that is not necessary.
  • switch and the plug are part of a one-piece switch unit. This not only simplifies the construction of the stop pawl, but saves conductors in the interior of the machine, especially, when still other structural parts (e.g. anti-interference means) are integrated in the power tool housing.
  • an at least partially elastic lever is mounted in the housing and held between two compression springs in a central position.
  • One of the compression springs may be braced between the switch handle and the lever, while the other may be braced between the housing and the lever.
  • the stop pawl is hook-like, comprises a bent free end portion of the lever and is urged into a space provided for receipt of the socket when the switch is in the "on" position.
  • the stop pawl may be engagable in a suitable opening in the socket to prevent unintended disconnecting of the socket.
  • the stop pawl is operable by a switch handle of the switch, which acts on the lever.
  • the lever is pivotally mounted at one end on a pivot in the housing and on the other end is movable by the switch handle of the switch via one of the compression springs.
  • FIG. 1 is a side elevational view of a hand-held power tool according to our invention to which the safety mechanism of the present invention is applicable,
  • FIG. 2 is a cross sectional view through a hand-held power tool showing the safety mechanism according to our invention.
  • FIG. 1 An angle sander as an example of a hand-held power tool or machine is shown in FIG. 1.
  • the rear portion on the opposite end from the tool 12 is shown in FIG. 2.
  • This type of angle sander is known for example from U.S. Pat. No. 4,434,586.
  • the invention is usable in all hand-held power tools with energy being fed over a cable or power cord, i.e. for all electrically powered line-supplied hand tools.
  • the hand-held power tool 10 has a plug 14 built into the housing 11 of the hand-held power tool, to which a socket 18 attached to a power cord 16 is connected.
  • the power cord 16 is not permanently nonreleasably attached to the power tool 10 and is connectable to the hand tool 10 only by the socket 18 as shown in FIG. 2.
  • Spring retaining clips 20, which cooperate with corresponding recesses 21 in the housing 11 of the hand-held power tool, are cast or molded on socket 18 as a safety device preventing unintended removal of the socket from the plug 14.
  • the plug 14 is connected electrically with a switch 22, which feeds electrical energy to electric motor 17 to drive the sanding tool 12 of the angle sander, in a switch unit 15.
  • the switch 22 is controlled by a switch handle 24 to be described in more detail below, which is mounted for easy gripping on the outer surface of the housing 11 of the hand-held power tool 10.
  • the switch unit 15 is attached to a connector member 26, which is connected in a known way with the pole piece of the stator 28 of the motor 17 and and carries the commutator brushes of the motor 17.
  • An anti-interference condenser 23 is mounted directly on the switch unit 15, advantageously with a plug-socket connection.
  • electronic components 25 may be mounted on the switch unit 15 or, as illustrated, on the connector member 26.
  • the switch handle 24 is inserted with its end 27 functioning as a pivot point in a slot or recess in the housing 11 of the hand-held power tool 10; spaced from the end 27 the switch handle 24 has a sliding push button member or slider 30 carries a push button member 24 on the outside, which is connected with a lock member 32 extending through a slot 31 in the switch handle 24.
  • the lock member 32 has two legs 35 and 37 standing at right angles to the motion direction of a sliding push button member 30, of which the leg 35 on the right in the drawing is longer than the left leg 37 and has a hook 33.
  • a stop stud 36--in the embodiment with the connector member 26-- is positioned opposite the lock member 32.
  • the stop stud 36 is in the form of a four cornered eye in whose opening 39 the hook 33 engages and can be locked in.
  • the lock member 32 is slidable with the sliding push button member 30 against the restoring force of a compressible spring 34 toward the switch handle 24 along the slot 31. In the condition not acted on by manual forces the sliding push button member 30 is pressed to the right by the compressible spring 34, which engages on the lock member 32 and braces itself on the switch handle 24.
  • the switch handle 24 has a surface 29, which acts on a switch pin 44 of the switch 22, on the side facing the housing interior; it is connected moreover by a compressible spring 54 with a lever 40.
  • This latter lever is mounted pivotable on the switch 22 about an pivot 42 in this embodiment.
  • the lever 40 has an opening for a switch pin 44 of the switch 22 and extends with its free end which is bent like a hook in the vicinity of the plug 14.
  • the hook-like free end portion of the lever 40 functioning as a stop pawl 46 is insertable through an opening in a side wall of the plug 14 in front of the opening 48.
  • the switch handle 24 can be depressed only with the sliding push button member 30 pushed to the left in the drawing for protection against unintended activation.
  • a contacting surface 38 formed on the free end of the left leg 37 of the lock member 32 prevents the pressing in of the switch handle 24 with the sliding push button member 30, since it contacts on the stop stud 36.
  • the eye-shaped stop stud 36 cooperating with the lock member 32 engages the hook 33 of the lock member 32 and thus the switch handle 24 is kept in the pressed in position.
  • the depressed state of the switch handle 24 is released by applying a new pressure to it; the compression spring 34 pushes the lock member 32 to the right in the drawing and releases the lock stud 36 from the hook 33. Now it is possible to connect the hand-held power tool to the line current supply.
  • the stop pawl 46 is urged toward the outer surface of the socket 18 by action of the compression spring 54.
  • the compression spring 52 acts as a restoring spring here.
  • the use of an elastic lever 40 allows one or even both compression springs 52 and/or 54 used in this embodiment to be left out of the apparatus.
  • this safety device is not limited to the combination with the illustrated switching characteristics.
  • the locking switch illustrated here could also be a simple key, a dead man switch, a two handle switch or some other suitable type of switch. However, in each case it is possible to provide a locking mechanism to be operated or activated unconsciously to prevent an unintended activation of the machine, as has already been required by law in Scandanavia.

Landscapes

  • Details Of Connecting Devices For Male And Female Coupling (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
US07/377,702 1988-07-28 1989-07-10 Safety device in an electrically powered machine, especially a hand-held power tool Expired - Fee Related US4970355A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3825654A DE3825654A1 (de) 1988-07-28 1988-07-28 Sicherheitseinrichtung an einer handwerkzeugmaschine
DE3825654 1988-07-28

Publications (1)

Publication Number Publication Date
US4970355A true US4970355A (en) 1990-11-13

Family

ID=6359760

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/377,702 Expired - Fee Related US4970355A (en) 1988-07-28 1989-07-10 Safety device in an electrically powered machine, especially a hand-held power tool

Country Status (4)

Country Link
US (1) US4970355A (enrdf_load_stackoverflow)
CH (1) CH679349A5 (enrdf_load_stackoverflow)
DE (1) DE3825654A1 (enrdf_load_stackoverflow)
GB (1) GB2223364B (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5638945A (en) * 1996-06-10 1997-06-17 Ryobi North America, Inc. Locking trigger mechanism for a portable power tool
US5654595A (en) * 1994-12-29 1997-08-05 Ferguson; Thomas R. Electrical current regulating device for a power tool
US5880420A (en) * 1997-04-11 1999-03-09 Pass & Seymour, Inc. Switch operator with interlock mechanism
US6153838A (en) * 1998-03-04 2000-11-28 Black & Decker Inc. Switch lock-off mechanism
US20030117095A1 (en) * 2001-08-06 2003-06-26 Bhanu Gorti Excitation circuit and control method for flux switching motor
US20030225039A1 (en) * 2002-05-10 2003-12-04 Frieder Bauss Method of treatment using bisphosphonic acid
US20040155532A1 (en) * 2003-02-07 2004-08-12 Brotto Daniele C. Method for sensing switch closure to prevent inadvertent startup
US20060091161A1 (en) * 2004-11-03 2006-05-04 Jianli Cen Portable electric grease gun

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4008161C1 (en) * 1990-03-15 1991-05-23 Telefunken Electronic Gmbh, 7100 Heilbronn, De Integrated circuitry projecting and controlling electrical appts. - has voltage limiter delivering pulse signal to counter if mains voltage is applied in-front of main switch
DE4216162C2 (de) * 1991-07-26 1996-04-04 Standard Establishment Mechanische Verriegelung an einer Steckverbindung zwischen einem elektrischen Schalter und einem Verbindungsstecker
JP3710697B2 (ja) 2000-09-19 2005-10-26 株式会社マキタ 往復動切断工具
JP3853590B2 (ja) * 2000-12-15 2006-12-06 株式会社マキタ 電動工具
DE102007054805A1 (de) 2007-11-16 2009-05-20 Tridonicatco Schweiz Ag Schaltungsanordnung zum Betreiben von Gasentladungslampen, bspw. HID-Lampen

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3212938A (en) * 1962-10-17 1965-10-19 Black & Decker Mfg Co Switch for cordless electrical device
US3881081A (en) * 1973-03-30 1975-04-29 Bosch Gmbh Robert Trigger mechanism for a power tool
US4280026A (en) * 1977-11-21 1981-07-21 Black & Decker Inc. Actuator mechanism for a portable, hand-held tool
US4335286A (en) * 1980-02-25 1982-06-15 Gunnar Nelson Waterproof electrical switch
US4604505A (en) * 1985-05-17 1986-08-05 Ero, Inc. Switch-plug interlock

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB488312A (en) * 1937-03-18 1938-07-05 Gen Electric Co Ltd Improvements in or relating to combined electric switch and socket units
GB551891A (en) * 1941-09-09 1943-03-15 Arthur William Chapman Improvements relating to sliding doors, roofs, windows, seats and the like
NL96394C (enrdf_load_stackoverflow) * 1957-02-26
GB974062A (en) * 1962-04-05 1964-11-04 Cole E K Ltd Improvements in or relating to mains/battery operated electrical apparatus
IT8120969U1 (it) * 1981-03-04 1982-09-04 Star Utensili Elett S P A Interruttore perfezionato per utensili elettrici
GB8312756D0 (en) * 1983-05-10 1983-06-15 Electropatent Ltd Electric sockets

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3212938A (en) * 1962-10-17 1965-10-19 Black & Decker Mfg Co Switch for cordless electrical device
US3881081A (en) * 1973-03-30 1975-04-29 Bosch Gmbh Robert Trigger mechanism for a power tool
US4280026A (en) * 1977-11-21 1981-07-21 Black & Decker Inc. Actuator mechanism for a portable, hand-held tool
US4335286A (en) * 1980-02-25 1982-06-15 Gunnar Nelson Waterproof electrical switch
US4604505A (en) * 1985-05-17 1986-08-05 Ero, Inc. Switch-plug interlock

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5654595A (en) * 1994-12-29 1997-08-05 Ferguson; Thomas R. Electrical current regulating device for a power tool
US5638945A (en) * 1996-06-10 1997-06-17 Ryobi North America, Inc. Locking trigger mechanism for a portable power tool
US5880420A (en) * 1997-04-11 1999-03-09 Pass & Seymour, Inc. Switch operator with interlock mechanism
US6153838A (en) * 1998-03-04 2000-11-28 Black & Decker Inc. Switch lock-off mechanism
CN1127741C (zh) * 1998-03-04 2003-11-12 布莱克和德克尔公司 开关中断锁定机构
US20030117095A1 (en) * 2001-08-06 2003-06-26 Bhanu Gorti Excitation circuit and control method for flux switching motor
US6943510B2 (en) 2001-08-06 2005-09-13 Black & Decker Inc. Excitation circuit and control method for flux switching motor
US20030225039A1 (en) * 2002-05-10 2003-12-04 Frieder Bauss Method of treatment using bisphosphonic acid
US20040155532A1 (en) * 2003-02-07 2004-08-12 Brotto Daniele C. Method for sensing switch closure to prevent inadvertent startup
US7112900B2 (en) 2003-02-07 2006-09-26 Black & Decker Inc. Method and system for sensing switch position to prevent inadvertent startup of a motor
US20060091161A1 (en) * 2004-11-03 2006-05-04 Jianli Cen Portable electric grease gun
US7267198B2 (en) * 2004-11-03 2007-09-11 Jianli Cen Portable electric grease gun

Also Published As

Publication number Publication date
GB8916312D0 (en) 1989-08-31
GB2223364A (en) 1990-04-04
DE3825654A1 (de) 1990-02-01
GB2223364B (en) 1992-07-22
DE3825654C2 (enrdf_load_stackoverflow) 1992-12-10
CH679349A5 (enrdf_load_stackoverflow) 1992-01-31

Similar Documents

Publication Publication Date Title
US4970355A (en) Safety device in an electrically powered machine, especially a hand-held power tool
KR100576952B1 (ko) 전기 기구 모듈용 로킹 장치를 구비한 저전압 스위치 기어
US4491752A (en) Electrical connection system for switches
US5983444A (en) Vacuum cleaner with a motor casing
US5346342A (en) Shaft lock arrangment for a power tool
GB2356496A (en) Connector with twist and lock securing means
CA2012022A1 (en) Electric module latch assembly
US4588910A (en) Reversing switch arrangement for an electric tool
JPH09183083A (ja) 手持ち工具機械
US20070277987A1 (en) Power tool, battery pack, and method of operating the same
JP2003523600A (ja) 改良された電気ソケット及びプラグ
US4328405A (en) Trigger switch and printed circuit board arrangement for a portable tool
US4345122A (en) Detachable cord
KR20230032899A (ko) 커넥터 장치
KR100423223B1 (ko) 전원 절환 개폐기의 자동절환 스위치
EP0896351A3 (de) Anordnung zum mechanischen Ankoppeln eines Ueberlastrelais an einem Schütz
AU2002354307A1 (en) Electrical working machine
US4164813A (en) Electrically powered knife
US7767918B2 (en) Power tool
GB2409770A (en) Electrical machine tool
US3691327A (en) Circuit-closing adapter
US4442366A (en) Switch-plug module for portable electric tool
CN115347311B (zh) 电动工具
US6126469A (en) Automatic door panel-to-body trim panel electrical connector with lever
KR200175161Y1 (ko) 전원 플러그 이탈수단을 가지는 콘센트

Legal Events

Date Code Title Description
AS Assignment

Owner name: ROBERT BOSCH GMBH, ROBERT-BOSCH-PLATZ 1, D-7000, S

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:HAEUSSLEIN, FRIEDRICH;STAEBLER, MANFRED;REEL/FRAME:005100/0619;SIGNING DATES FROM 19890613 TO 19890614

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Free format text: PAYER NUMBER DE-ASSIGNED (ORIGINAL EVENT CODE: RMPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
FP Lapsed due to failure to pay maintenance fee

Effective date: 19981113

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362